Process for improving abrasion resistance of resilient fabrics and the product produced

ABSTRACT

Wet fixation of N-methylol resins to produce cotton fabrics suitable for durable press may be achieved through the use of inert additives in the fixation step. The fixation step may be carried out in conventional equipment used for drying textiles. The inert additive apparently prevents collapse of the fiber during the fixation-drying step.

United States Patent Vail et al.

[ Apr. 15, 1975 PROCESS FOR IMPROVING ABRASION RESISTANCE OF RESILIENTFABRICS AND THE PRODUCT PRODUCED Inventors: Sidney L. Vail, New Orleans,La.;

Alvin H. Young, New York, N.Y.; Gerald B. Verburg, Metairie, La.

The United States of America as represented by the Secretary ofAgriculture, Washington, DC.

Filed: Oct. 6, 1972 Appl. No.: 295,778

Related US. Application Data Continuation-in-part of Ser. No. 772,386,Oct. 31, 1968, abandoned.

Assignee:

US. Cl. 8/183; 8/1 15.6; 8/186;

8/187 Int. CL... D06m l/00 Field of Search 8/1l5.6, 116.4, 181, 183,

[56] References Cited UNITED STATES PATENTS 3,434,794 3/1969 Tovey8/116.4 X 3,451,763 6/1969 Weiss 8/1 16.4 X 3,658,458 4/1972 Gale 8/116.4 X

Primary Examiner -Stephen J. Lecher't, Jr. Attorney, Agent, or FirmM.Howard Silverstein; Max D. Hensley [57] ABSTRACT 4 Claims, No DrawingsPROCESS FOR IMPROVING ABRASION RESISTANCE OF RESILIENT FABRICS AND THEPRODUCT PRODUCED A non-exclusive, irrevocable, royalty-free license inthe invention herein described, throughout the world for all purposes ofthe United States Government. with the power to grant sublicenses forsuch purposes. is hereby granted to the Government of the United Statesof America.

This is a continuation-in-part of application Ser. No. 772,386, nowabandoned, filed Oct. 31, 1968.

The search for improved methods of treatment of cotton to producecommercially acceptable durablepress fabrics has resulted in several newprocesses. One of the more promising, a wet-fixation process. was firstintroduced by the National Cotton Council of America in 1966 [TextileResearch Journal 37. 70 (1967)]. It involves the fixation of apolymer-former and a crosslinker to cotton fabric under aqueous, acidicconditions. In this laboratory process the fabric, padded with thesolution of reagents at a pH of 2, is heated in a sealed container(plastic bag) to achieve fixation of the resins. The first or fixationstep appears to be the more important phase of the process. Part of theresin content is firmly fixed in the cotton fibers and the fabric, afterrinsing and application of catalysts and softener, can be used in theproduction of durable-press garments.

A major advantage of the process is that an essentially odorless,sensitized fabric is produced for use in the manufacture ofdurable-press garments. in addition, the cured fabrics are smooth dryingwith less impairment of tearing strength and Stoll flex abrasion thanconventionally treated fabrics with equivalent smooth-drying properties.

The purpose of the present study is to improve the process in apractical sense. Laboratory procedures have been studied which arepotentially more adaptable to commercial finishing. More specifically,this application deals mainly with a major process variation of thetreatment, i.e., fixation of the resins in a semi-dry state in thepresence of an inert additive. The fixation step, as described in thisinvention, may be carried out using conventional equipment used fordrying textiles. The fixation can be carried out rapidly in an openstate and no bag or container is required. Further, the amount of resinrequired on the fabric is much lower than conventional treatments, i.e.,resins add-ons in this invention are from about 3 to 6 percent.

These and some of the other advantages of this process are seen in thefollowing general description.

1 Cellulosic fabric is padded through a resin bath at a pH of about 2which contains 10-20 percent of a methylated methylolmelamine (hereafterabbreviated MMM), -20 percent of another cross-linking agent, and -20percent of an inert additive.

2 In the fixation step, the wet fabric is partially dried in an oven toremove part of the water present. Time and temperature for this stepwill depend upon the weight of the fabric used. Satisfactory conditionsfor a 3.0-3.5 02. printcloth are three minutes at 58C.

These conditions must be such that the resin add-on (calculated afterstep 3) is less than 8 percent. Also these conditions must be such thata high degree of polymerization of the reactants is not achieved. i.e.,the materials fixed in the fabric must be highly capable of furthercrosslinking of the cellulose. Conditions which favor the polymerizationreaction at this point produce a boardy fabricwhich cannot be used toproduce a durable press fabric with acceptable strength and resistanceto abrasion;

3 The partially dried fabric is neutralized, washed, and dried.

4 Curing catalyst and softeners (or other auxiliaries) are added to thefabric in a conventional manner.

5 Fabric is dried and treated as a sensitized fabric for durable press.

Many MMM resins are satisfactory for this process. However, those resinswhich contain from at least one to six methoxymethyl groups and one ortwo methylol groups (where possible) appear to be preferred. Themethylation of the methylolmelamines should be carried out underconditions which keep polymerization at a minimum.

The second crosslinking agent can be selected from a number of agentsbut N,N-dimethylol carbamates or N,N'-dimethylol dihydroxyethyleneurea(DMDHEU) generally are preferred.

Inert additives were selected from a group of materials which wereexpected to keep the cellulosic fiber (cotton, for example) in a swollenstate. Such materials include tetraethylene glycol dimethyl ether(abbreviated TDM). Zinc nitrate or magnesium chloride has been found tobe satisfactory as curing catalyst. Emulsified polyethylene was used assoftener when a softener was desired.

Valko, et al. [Textile Research Journal 37, 253 1967)] have recentlydiscussed the use of nonreactive and co-reactive additives for thepurpose of obtaining an improved abrasion resistance-wrinkle-recoveryangle relationship. Our work with the same twocomponent system (melamineplus cross-linker) was performed under different conditions than thoseused by Valko and has produced different effects. A highlywrinkle-resistant, abrasion-resistant cotton fabric can be obtained fromthe fixation of a two-component system which has a swelling agentpresent. The aqueous resin mixture-TDM solution at pH of about 2, ispadded onto cotton fabric, and the wet fabric is heated in an oven untilit is barely moist to the hand. From this point on, it is treated in thesame manner as any other wetfixed fabric. Our process is different fromValkos double cure of two-component systems in at least two importantrespects: (1) A higher percentage of reactants are required, and (2) thefixation conditions or first cures" are much milder, e.g., 58C. for 3-4minutes rather than C. for 15 minutes. For simplicity the process ofthis invention will be called moist fixation.

Table I compares various fixation conditions and their effect upon thephysical properties of the fixed and the cured fabric.

Fixation for 15 minutes at 82 provides the equivalent of a harsh,conventional pad-dry-cure finish. Abrasion resistance of the curedfabric is very poor. The milder fixation conditions of 3 minutes at 58provides a sensiin the art. In the examples, all parts and percentagesare by weight unless noted otherwise. The fabrics were tested by thefollowing methods: Wrinkle recovery an,

gle, Monsanto method, American Society for Testing for the production ofan acceptable finished textile. Many variations or additions withinthese procedures can be made, as will be readily apparent to thoseskilled tized fabric which can be used to produce an abrasion 5Materials (ASTM) test D l295-6OT; tearing strength, andwrinkle-resistant fabric with only a moderate add- Elmendorf method,ASTM test D 1424-63, Stoll flex on of resin. The moderate wrinkleresistance can be imabrasion resistance, ASTM test D l l75-64T; Bothproved through the use of more reagents and/or use of abrasion andtearing strength are reported as percent. softeners as shown in TableII. of theoriginal, untreated fabric which had been:laun- TABLE llProcedures Wrinkle and Paid Recovery Bath Abrasion Angle TearingConcentrations Fixation Resistance (W+F) Strength as in: Conditions (/1of orig.) (deg) (/1 of orig.)

Example 3 3 min/58 H4 285 98 Example 4 (1 min/50 72 295 82 The effectsof the use of polyurethanes (an elastof f Once- Thls noted m the molesas fl mer) in the various treatments are noted in Table III. EXAMPLE 1The polyurethane was obtained from Wyandotte Chemicals Corporation andwas identified as E-406A. 25 An 80 X 80 cotton printcloth (3.4 oz/sq.yard), which The material may be further described as anionic, had beendesized, scoured, and bleached. was padded emulsifiable, high molecularweight polymers that form in the usual manner with two dips and twotrips in the strong elastic films upon drying and heat-fusing thefollowing aqueous pad bath which had been adjusted to polymer particlesat elevated temperatures. pH 2 with hydrochloric acid:

TABLE III Procedures Wrinkle and Pad Bath Abrasion Recovery TearingConcentrations Fixation Resistance Angle W-i-F) Strength as in:Conditions (71 of orig.) tdeg.) (/2 of orig.)

Example 1 5 min/58 [54 27l 92 Example 6 l 5 min/58 3ll 293 98 Example 7'4 5 min/58 262 299 96 No polyurethane pretreatment In Examples 6 and 7the polyurethane was applied to First Pad Bath the cotton'fabric beforemoist fixation. However. if the R I P polyurethane emulsion iscompatible with the softener- Cree" curing catalyst system, it can beadded at this point. MMM The polyurethane is particularly useful insituations SS 3 where the wrinkle recovery angles of the treated fabricsfrom a process are in need of being increased. If the I The wet fa nc wpolyurethane (or other, elastomer) is used prior to b as h l q on a pmfiame and I heated under the fixation conditions shown in the tamoistfixation, then the elastomer must be able to resist bles Fonowinfixation the fabric was Washed imm di hydrolysis under the acidic (pHzz)Conditions of the ately to remofe the acid and any unreacted mater ialsd bat containin the ol mer-formers and crossq, f h g p y and then dried.The fixed fabric was then padded as lmkers' before in an aqueous padbath with the following com- The processes of this tnventlon can be usedto treat Osition substantially any hydrophilic fibrous cellulosicmaterial p (including blends) such as cotton, rayon, ramie, jute. 5mm!PM and the like. Reagent Percent The following examples are given by wayof illustration and'not by way of limitation of the invention. TheMagnesum chlmdc hcmhydw'c 4 detailed procedures given below in theexamples are illustrative, and are not the only or specific conditions,5 The wet fabric was again pinned on a pin frame and dried in an ovenat 60C. for seven minutes. Final curing of the resins was obtained in asecond oven by heating the fabric on a pin frame for three minutes at160C. The fabric was washed and dried prior to testing. See theappropiate table for testing results.

EXAMPLE 2 Same as Example 1 except the concentration of TDM in the firstpad bath was 20 percent.

Second Pad Bath Zinc nitrate hexahydrate Poly-ethylene solids EXAMPLE 4Same as Example 3 except the second pad bath had the followingcomposition:

Second Pad Bath Reagent Percent Magnesium chloride hexahydrate 4.0Polyethylene solids 2.0

EXAMPLE 5 Same as Example 4 except a seven ounce twill fabric was usedinstead of the printcloth and the percentage of magnesium chloridehexahydrate in the second pad bath was 2.0 percent EXAMPLE 6 Same asExample 5 with the following changes:

The fabric was given a pretreatment prior to padding in a second padbath. In this pretreatment the fabric was padded with an aqueousemulsion containing 12 percent polyurethane (E-406A, supplied byWyandotte Chemicals Corporation) and the wetted fabric was dried for tenminutes at 60C.

EXAMPLE 7 Same Example example 6 except that the second pad bathcontained:

Second Pad Bath Reagent Percent MMM 20 Dimethylol isopropyl carbamate 20TDM 20 We claim:

. l. A process for treating a cellulosic fabric to produce acommercially acceptable durable-press fabric which process consists of:

padding the cellulosic fabric through a resin bath at a pH of about2which bath contains from about 10 to 20 weight percent of a methylatedmethylolmelamine, from about 5 to 20 weight percent of a crosslinkingagent selected from a group consisting of N,N-dimethylol carbamates andN,N'- dimethylol dihydroxyethyleneurea and from about 10 to 20 weightpercent of tetraethylene glycol dimethyl ether,

b. heating the padded cellulosic fabric in an open state at atemperature of about 58 C- for a period of about 3 minutes to permitunrestrained evaporation of moisture from said fabric and, without anyfurther heating, then neutralizing, washing and drying the cellulosicfabric,

. padding the washed and dried cellulosic fabric from step (b) with anaqueous solution free of crosslinking agent and containing from about0.5 to 4.0 weight percent of an acid catalyst selected from a groupconsisting of magnesium chloride hexahydrate and zinc nitratehexahydrate and from about 0 to 2 weight percent of emulsifiedpolyethylene,

d. drying the cellulosic fabric from step (e) for a period of about 7minutes at a temperature of about 60 C., and

(e) curing the fabric from step (d) for a period from about 3 to 5minutes at a temperature of about C.

A process for treating a cellulosic fabric to produce a commerciallyacceptable durable-press fabric which process consists of:

padding a cellulosic fabric in an aqueous solution containing about 12weight percent of an anionic. emulsifiable, high molecular weightpolyurethane.

b. drying the padded cellulosic fabric for a period of about 10 minutesat a temperature of about 60 C.,

padding the cellulosic fabric from (b) through a resin bath which bathcontains from about 10 to 20 weight percent of a methylatedmethylolmelamine. from about 5 to 10 weight percent ofa crosslinkingagent selected from a group consisting of N,N- dimethylol carbamates andN,N'-dimethylol dihydroxyethyleneurea and from about 10 to 20 weightpercent of tetraethylene glycol dimethyl ether,

(1. heating the cellulosic fabric from (c) in an open state at atemperature of about 58 C. for a period of about 3 minutes to permitunrestrained evaporation of moisture from said fabric and, without anyfurther heating, then neutralizing, washing and drying the cellulosicfabric,

padding the washed and dried cellulosic fabric from step (d) with anaqueous solution free of crosslinking agent and containing from about0.5 to 4.0 weight percent of an acid catalyst selected from a groupconsisting of magnesium chloride hexahydrate and zinc nitratehexahydrate and from about 0 to 2 weight percent of emulsifiedpolyethylene,

drying the cellulosic fabric from step (e) for a period of about sevenminutes at a temperature of about 60 C., and

g. curing the fabric from step (f) for a period from about 3 to 5minutes at a temperature of about l60.

3. The product produced by the process of claim 1. 4. The productproduced by the process of claim 2.

1. A PROCESS FOR TREATING A CELLULOSIC FABRIC TO PRODUCE A COMMERCIALLYACCEPTABLE DURABLE-PRESS FABRIC WITH PROCESS CONSISTS OF: A. PADDING THECELLULOSIC FABRIC THROUGH A RESIN BATH AT A PH OF ABOUT 2 WHICH BATHCONTAINS FROM ABOUT 10 TO 20 WEIGHT PERCENT OF AMETHYLATEDMETHYLOLMELAMINE, FROM ABOUT 5 TO 20 WEIGHT PERCENT OF A CROSSLINKINGAGENT SELECTED FROM A GROUP CONSISTING OF N,N-DIMETHYLOL CARBAMATES ANDN,N''-DIMETHYLOL DIHYDROXYETHLENEUREA AND FORM ABOUT 10 TO 20 WEIGHTPERCENT OF TETRAETHYLENE GLYCOL DIMETHYL ETHER, B. HEATING THE PADDEDCELLULOSIC FABRIC IN AN OPEN STATE AT A TEMPERATURE OF ABOUT 58*C. FOR APERIOD OF ABOUT 3 MINUTES TO PERMIT UNRESTRAINED EVAPORATION OF MOISTUREFROM SAID FABRIC AND, WITHOUT ANY FURTHER HEATING, THEN NEUTRALIZING,WASHING AND DRYING THE CELLULOSIC FABRIC, C. PADDING THE WASHED ANDDRIED CELLULOSIC FABRIC FROM STEP (B) WITH AN AQUEOUS SOLUTION FREE OFCROSSLINKING AGENT CONTAINING FROM ABOUT 0.5 TO 4.0 WEIGHT PERCENT OF ANACID CATALYST SELECTED FROM AGROUP CONSISTING OF MAGNESIUM CHLORIDEHHEXAHYDRATE ANDZINC NITRATE HEXAHYDRATE AND FROM ABOUT 0 TO 2 WEIGHTPERCENT OF EMULSIFIED POLYETHYLENE, D. DRYING THECELLULOSIC FABRIC FROMSTEP (C) FOR A PERIOD OF ABOUT 7 MINUTES AT A TEMPERATURE OF ABOUT60*C., AND (E) CURING THE FABRIC FROM STEP (D) FOR A PERIOD FROM ABOUT 3TO 5 MINUTES AT A TEMPERATURE OF ABOUT 160*C.
 2. A process for treatinga cellulosic fabric to produce a commercially acceptable durable-pressfabric which process consists of: a. padding a cellulosic fabric in anaqueous solution containing about 12 weight percent of an anionic,emulsifiable, high molecular weight polyurethane, b. drying the paddedcellulosic fabric for a period of about 10 minutes at a temperature ofabout 60* C., c. padding the cellulosic fabric from (b) through a resinbath which bath contains from about 10 to 20 weight percent of amethylated methylolmelamine, from about 5 to 10 weight percent of acrosslinking agent selected from a group consisting of N, N-dimethylolcarbamates and N,N''-dimethylol dihydroxyethyleneurea and from about 10to 20 weight percent of tetraethylene glycol dimethyl ether, d. heatingthe cellulosic fabric from (c) in an open state at a temperature ofabout 58* C. for a period of about 3 minutes to permit unrestrainedevaporation of moisture from said fabric and, without any furtherheating, then neutralizing, washing and drying the cellulosic fabric, e.padding the washed and dried cellulosic fabric from step (d) with anaqueous solution free of crosslinking agent and containing from about0.5 to 4.0 weight percent of an acid catalyst selected from a groupconsisting of magnesium chloride hexahydrate and zinc nitratehexahydrate and from about 0 to 2 weight percent of emulsifiedpolyethylene, f. drying the cellulosic fabric from step (e) for a periodof about seven minutes at a temperature of about 60* C., and g. curingthe fabric from step (f) for a period from about 3 to 5 minutes at atemperature of about 160*.
 3. The product produced by the process ofclaim
 1. 4. The product produced by the process of claim 2.